Fluid compressor



Dec. 22, 1936. A TRAsK FLUID COMPRESSOR Filed Sept 30, 1935 3 Sheets-Sheet l /wq 9 l Z f y w w e Z U .w 0

Dec. 22, 1936. A. TRAsK 2,065,162

FLUID COMPRES SOR Filed Sept. 30,' 1935 3 Sheets-Sheet 2 Dec. 22, 1936. A. TRAsK I 2,0653162 FLUID COMPRESSOR Filed Sept. 50, 1933 3 Sheets-Sheet' 3 Patented Dec. 22, 1936 PATENT OFFICE 2,085482 FLUrn commnssoa Allen 'rr-ask, ozk Park, iu., assignor to Mms Novelty Company, Chicago, Ill., a corporation of Illinois Application September 30, 1933, Serial No. 691,601

12 Claims.

- This invention relates to fluid compressors and more particularly to a sealed type of fluid compressor adaptable to an.. electric refrigerating system.

It is one of the objects of the invention to silence the noise of compressor operation by mufiling the fluid intake;

It is another object of the invention to minimize superheating of the inlet fluid by the heat of compressionv and the heat of an integral electric motor.

It is also an object of the invention to provide pressure lubrication to all rotating bearing surfaces without the addition of parts for that specific purpose.`

Still another object is the provision of a valve system of inlet and discharge valves involving a minimum of clearance at the end of the discharge stroke, and thus a. minimum loss of 20 volumetric emciency due to clearance and its attendant re-expansion loss.

A further object is the dissipation of compressor vibration so that it will not be transmitted through its supports.

A still further object of the invention is to provide a means to prevent lubricating oil from being thrown from the connecting rod bearing and eccentric into the pistons and cylinders where it would be carried by the low pressure 30 fluidA through a piston head inlet valve into the high pressure side of thesystem.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is shown.

In the drawings:

Figure 1 shows a Vertical cross sectional view of a compressor embodying the invention,

Figure 2 shows a top cross sectional view of the compressor through section line 2-2 shown in Figure 1,

Figure 3 is a part sectional view of the compressor shown from the side opposite the one shown in Figure 1. This view shows an enclosed crank case in section, the discharge manifold between the two cylinder heads, and the intake passage into the crank case,

Figure 4 is a view of the compressor drive shaft that shows the intemal oil passages and the external helical oil grooves,

Figure 5 shows the sectional view, on section line 5-5 of Figure 3 through the closed crank case, showing tubing connection to the discharge manifold,l and the fluid inlet tube into the enclosed crank case,

Figure 6 shows the sectional view shown on section line 6-6 through the closedv crank case shown in Figure 3, showing a sectional view through the side of the crank case opposite the crank case cover, and a sectional view through the integral discharge manifold,

Figure 7 is a view of the compression end of one of the pistons. This shows the annular inlet groove and a hole for the passage of inlet fluid from the interior of the piston to the annular inlet groove,

Figure 8 shows a top view of the crank case cover and the lubricating oil baflie as it is shown in section in Figure 2,

Figure v9 is a cut away and partically sectioned side view of the bafile as shown in Figure 8,

` Figure 10 shows a cross sectional view through section line Ill-IO of Figure 1. This section shows the shaft oil passages leading through the eccentric to the connecting rod bearings at a 90 degree angle from the view of those parts shown in Figure 1, i

Figure 11 is a cross sectional view of one of the pistons, an inlet valve, an inlet valve damping disc, an inlet valve button and the rivet for securing together these four parts in thesame relation that they are shown in Figures 1 and 2.

As an example of an embodiment of the inlvention in a compressor Figure 1 shows a vertical cross sectional view of a hermetrically sealed type electric compressor adaptable to a household mechanical refrigerator.

A cylindrical housing l hermetically encloses the mechanism by the welded in base 2. The stator 3 of an electric motor energizes the rotor 4 which secured to the drive shaft 5, operates the compressing mechanism below.

The crank case 6 closed by cover 'l provides support for upper shaft bearing 8 and lower shaft bearing 9, and encloses eccentrics IO from which are operated rods H, and pistons l2. On opposite sides of crank case 6 are cylinders |3, and cylinder heads 14.

An inlet tube |5 sealed to outer housing l at its point of passing through said housing, leads the inlet fluid directly into crank case 6. Thus the inlet fluid is prevented by the closed crank case 6 from circulating into contact with the cylinders |3, the cylinder heads |4, and electric motor parts, where' by the heat of compression and electrical resistance respectively, it would become superheated and thus expanded before compression. This superheating expansion is prevented by closed crank case 6 so that the compressor is assured of a better volumetric efiiciency than it would otherwise have without said closed crank case 6.

Circular fiexible disc inlet valves |6 and fiexible inlet valve damping discs I'I are secured concentrically to the heads of pistons |2.by inlet valve buttons |8 and valve button rivets |9. Under the periphery of inlet valve |6 are annular inlet grooves 20 and holes 2| in the heads of pistons |2 providing a passage for the inlet fiuid to fiow from the closed crank case 6 through piston heads and-around the annular grooves 20 under the peripheries of the inlet valves |6. On the inlet or` suction strokes of the pistons the difference in pressure between the fiuid in the crank case 6, and the compression chambers between the piston heads and the cylinder heads, will cause the fiuid to fiow from the closed crank case 6, through piston inlet holes 2|, around annular grooves 20 where said pressure difference will be exerted against the under side of the rim of the intake valves |6, causing them to defiect to allow passage of said inlet fiuid into said compression chambers as the pistons cover their inlet strokes.

Annular grooves 20 perform a very important function in allowing the inlet fiuid to fiow into the cylinders under the entire peripheries of the inlet valves IB, so that the maximum intake will cause a minimum of valve lift as they are sprung from their seats by the inlet fiuid.

On the compression strokes of the pistcns, the pressure rise in the compression chambers causes the inlet valves |6 to seat firmly against the heads of pistons |2, to prevent passage of the compressed fiuid back into annular grooves 20 and thence into closed crank case 6.

As heretofore mentioned, inlet valve damping discs are secured to the heads of pistons |2 with the inlet valves |6 in the relative position shown in Figure 11. These damping discs are thin circular discs similar to the inlet valves, that act as vibration dampeners to prevent the inlet valves from attaining periodic or harmonic vibrations in the path of fiow of the inlet fiuid. A lift by the inlet fiuid, of the inlet valves and damping discs from their normal position fiat on the piston h'eads, causes a sliding motion. between the two as between the leaves of a leaf spring. The friction of this sliding motion absorbs the energy that would otherwise cause the inlet valves to flutter or vibrate at high enough frequencies to cause a whistling noise. Thus, inlet valve damping discs in combination with inlet valve IS, assure more quiet compression than could be attained without them.

The usual Operating speed of this type of compressor, that is directly connected to an electric motor, is between 1700 and 1800 R. P. M. At this speed the intermittent fiowing 'of the inlet fiuid creates a noise similar to the exhaust noise one might expect from a miniature motor boat operating without a mufiier. Reduction to practice shows that outer housing i alone will not sufliciently prevent the transmission of this noise to the outside of the housing, to give the machine desirable quietness.

Reduction to practice shows, however, that the closed crankcase 6, enclosed within the outer housing to confine the inlet fluid as heretofore explained, will effectively confine the inlet fiuid -noise within said crank case so that such noise of compressor operation as is transmitted to the outside of outer housing will not be objectionaooaica able. Thus, closed crankcase B assures quietness of compressor operation that could not possibly be obtained without it.

The compression strokes of the pistons |2 force the fiuid through discharge openings 22 in cylinder heads M. Within cylinder heads H on the sides of the discharge openings 22 that are opposite the pistons 2, are discharge valves 23 a seated on discharge valve seats 24 and held in place by discharge valve springs 25. At the end of the compression stroke. valve buttons |8 fit within discharge openings 22 to displace and discharge the last bit of fiuid from within the cylinder. Thus .the space of the discharge opening 22 is prevented from retaining fiuid at the end of the compression strolres.v If that volume of fiuid was allowed to remain in discharge openings 22 it would expand back into the cylinder on the intake stroke. Thus less fresh inlet fiuid would be drawn'from the closed crankcase 6, and the volumetric efi'iciency of the compressor would be less than it is with valve buttons |8 fitting into discharge openings at the ends of the compression strokes.

From discharge valve chambers in cylinder heads |9 are discharge passages 26 leading to discharge manifold 27|. From discharge manifold 2`| the discharge fiuid is led through discharge tube' 28 to the outside of the outer housing that encloses the compressor. At the point of passage through outer housing I, discharge tube 28 is silver soldered to said outer housing.

It is a specific object of the invention to provide pressure lubrication to the rotating bearing surfaces of the compressor. In the machine of this invention that end is accomplished as follows:

Base plate 2 in itself provides a lubricating oil reservoir in which the bearing 9, at the lower end of shaft 5, is submerged. Within shaft 5 is an oil passage 29 that provides communication between lower shaft bearing 9, eccentric oil holes 30, and upper shaft bearing 8.

From the lower end of shaft 5 to the lower openings of shaft oil passage 29 are two oil grooves 3| spiraled as a right hand thread so that a clockwise rotation of shaft 5 will cause lubricating oil from' the supply in base plate 2,

to be lifted and forced into said shaft oil passage 29. Thus lower bearing 9 is provided with pressure lubrication, and from shaft oil pasage 29 through eccentric oil holes 30 the bearings of connecting rods are provided with pressure lubrication.

From the upper end of shaft oil passage 29 is a helical oil groove 32 spiraled also as a right hand thread to a thrust bearing 33, so that a clockwise rotation of shaft 5 will force oil up said spiral groove 32 and between the surfaces of said thrust bearing 33. Thus, upper shaft bearing 8 and thrust bearing 33 are provided with oil under pressure generated by the combined action of shaft spiral oil grooves 3| and 32.

It is particularly important that the two spiral oil grooves 3| at the lower end of shaft 5 have a much greater oil pumping capacity than the spiral groove 32 that supplies oil to the thrust bearing at the upper end of shaft 5. As shown, the two lower spiral grooves 3| have twice the pitch of the single upper spiral groove 32. Thus the lower spiral grooves 3| will pump substantially four times as much oil as is the capacity of the single upper spiral groove 32 of one half the pitch. This insures the maintenance of oil pressure at the connecting rod bearings in aocaioa the crankcase cover secures the oil bai'lle 34 inits desired position. This position of the 'oil baiiie is such that the connecting' rods ll function through narrow slots in the baille in such manner that lubricating oil that is thrown centri'fugally from the connecting rod bearings on the eccentrics shall be intercepted by the bailie in thel path that would carry the oil into the cylinders and pistons. Thus being prevented from entering the pistons, the oil cannot be carried through the inlet valve by the inlet fluid, and it will run to the base of the crankcase.

In the base of the crankcase 6 are oil passages 3G extending below the surface of the oil in the lubricant reservoir in the base plate 2.

Crankcase breather holes 31 are provided'in the crankcase cover 1 and the baflie plate 35, to equalize the fiuid pressure between the. inside and outside of the crankcase so that oil discharged from bearing surfaces within said crankcase, shall be free to fiow by the infiuence of gravity, back into the oil reservoir. 4

' An object of the invention is to provide a compre'ssor mounting that transmits a minimumv of Vibration to the support upon which it is mounted. This objective is obtained by mounting the compressor upon the supporting plate'38 in the following manner. In base 2 that is welded to the outer housing I, are three spherical pockets 39 disposed equidistant from the extended center line of Vertical shaft 5 and 120 degrees from each other. In these three pockets 39 are lcosely positioned three rubber balls 40, one in each pocket. In the support 38 are three sockets 4| disposed as are the spherical pockets 39 in base 2, so that the three rubber 'balls 40 support the compressor by fitting into these sockets 4|.

The radius ofthe spherical curvature of the pockets 39 and the sockets 4| is larger than the radius of the rubber balls 40, so that there is allowed a freedom for a rolling motion of the balls. The vibration or voscillation of the compressor is of a rotary nature and is in a horizontal plane about the central Vertical shaft 5 as an axis. This is because the rotary and reciprocating parts of the compressor all move in a horizontal plane about the shaft 5 as an axis.

Since the rubber balls 40 are disposed also in a horizontal plane in supporting the compressor, and are likewise equidistant from the same axis, shaft 5, the rotary Vibration of the compressor will not be transmitted to support 30, for the balls will rotate instead of transmitting the Vibration that causes them to rotate. Thus the balls 40 allow the compressor to assume, un-

resisted, its own natural period of Vibration. The fact that the balls are so disposed as not to resist this vibration, assures that the vibration will not be transmitted to the support 38 of the compressor.l

It must be understood that the eccentrics, connecting rods, pistons, cylinders and Valve mechanisms on both sides of Vertical shaft 5 are identical. Thus is provided a symmetry of design and a balanced smoothness of operation.

The fiuid compressor herein disclosed is a unitary structure adapted to be installed as a unit in a mechanical refrigerator. In this selfcontained unit there has been shown and described the means of attainment of the Various desirable objective hereinbefore set forth.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is:

l. In a machine of the class described, in combination, an outer housing, a motor, a cylinder, a crankcase, a piston in said cylinder, an inlet valve in the head of said piston, a fluid inlet passage from the exterior of said outer housing to the interior of said crankcase, a breather opening in said crankcase, an oil reservoir in the base of said outer housing,.means for supplying oil to bearing surfaces within said crankcase, and a lubricating oil outlet passage from said crankcase.

2. In a machine of the class described, in combination, a housing, a Vertical shaft, an electric motor mountedV on said Vertical shaft, an 'ec-` centric mounted on said Vertical shaft, a means f of compression operable by said eccentric, oil passages within said Vertical shaft, oil passages within said eccentric, the oil passages in said shaft communicating with the oil passages in said eccentric and the bearing surfaces of said Vertical shaft and eccentric, an oil reservoir at the base of said housing. and a helical oil groove .at the lower end of said Vertical shaft providing bearing surfaces above and below said eccentric for taking the radial load of said Vertical shaft, oil passages in said shaft and eccentric, said oil passages providing communication between said bearing surfaces and said connecting rod, a reservoir for lubricating oil, a spiral oil groove in said shaft, said spiral oil groove providing communication between said oil reservoir and said shaft oil passage.

4. In a machine of the class described, in combination, a cylinder, a piston in said cylinder, a Vertical shaft, an eccentric mounted on said Vertical shafts, a connecting rod operatively connected at one end with said eccentric and at the other end with said piston, a thrust bearing, bearing surfaces above and below said eccentric for taking radial load of said shaft, oil passages in said shaft and eccentric, said oil passages providing communication between said radial bearing surfaces and said connecting rod, a reservoir for lubricating oil, a spiral groove in said shaft, said spiral groove providing communication between said oil reservoir and said shaft oil passages, and a spiral groove in said shaft providing communication between said shaft oil passage and said thrust bearing.

5. In a machine of the class described, in combination, a cylinder, a piston in said cylinder, a Vertical shaft, an eccentric mounted on said Vertical shaft, a connecting rod operatively connected at one end with said eccentric and at the other end with said piston, a thrust bearing, bearing surfaces above and below said eccentric for taking radial load of said shaft, oil passages liu said shaft and eccentric, said oil passages providing communication between said radial bearing surfaces and said connecting rod, a reservoir for lubricating oil, a spiral groove in the lower end of said vertical shaft, said spiral groove providing communication between said oil reservoir and said shaft oil passages, and a spiral groove in the upper part of said shaft, said last mentioned spiral groove providing communication .between said shaft oil passage and said thrust bearing, said lower spiral groove being relatively of longer pitch than said upper spiral groove.

6. In a machine of the class described, in com- -bination, a cylinder, a piston in said cylinder, a

Vertical shaft, an eccentric mounted on said Vertical shaft, a connecting rod operatively connected at one end with said eccentn'c and at the other end with said piston, a thrust bearing, bearing surfaces above and below said eccentric for taking radial load of, said shaft, oil passages in said shaft and eccentric, said oil passages pro- Viding communication between said radial bearing surfaces and said connecting rod, a reservoir for lubricating oil, two spiral grooves in said shaft, said spiral grooves providing communication between said oil reservoir and said `shaft oil passages, and one spiral groove in said shaft providing communication between said shaft oil passage and said thrust bearing.

'7. Ina machine of the class described, in combination, a cylinder, a piston in said cylinder, a vertical shaft, an eccentric mounted on said Vertical shaft, a connecting rod operatively connected at one end with said eccentric and at the other end with said piston, a thrust bearing, bearing surfaces above and below said eccentric for taking the radial load of said shaft, oil passages in said shaft and eccentric, said oil passages providing communication between said radial bearing surfaces and said connecting rod. a reservoir for lubricating oil, two helical grooves at the lower bearing surface of said vertical shaft, said helical grooves providing communication between said oil reservoir and said shaft oil passage, and one helical groove at the upper bearing surface of said Vertical shaft, said last mentioned helical groove providing communication between said shaft oil passage and said thrust bearing, said lower helical grooves being of relatively longer pitch than said upper helical groove.

8. In a machine lof the class described, in`

combination, an outer housing having a lubricant reservoir formed in the lower portion thereof, an inner housing, said inner housing including a crank c-ase positioned above the maximum level of lubricant maintainable in said reservoir, a fluid inlet passage extending through said outer housing to the inside of said crank case, a cylinder in said inner housing communicating with said' crank case, a piston in said cylinder, said piston being operable to compress gaseous fluid, a fluid inlet valve in the head of said piston, and a fluid outlet passage extending from aooaioa the head of said cylinder through said outer housing.

9. In a machine of the class described, in combination, a cylinder, a piston in said cylinder, a vertical shaft, bearing surfaces for taking the radial load of said vertical shaft, an oil passage within said vertical shaft, said oil passage providing communication between said vertical shaft bearing surfaces, an oil reservoir, and a spiral oil groove, said spiral oil groove providing communication between said oil reservoir and said oil passage in said vertical shaft.

10. In a machine of the class described, in combinationI a cylinder, a piston in said cylinder, a vertical shaft, bearing surfaces for taking the radialload of said vertical shaft, an oil passage within said vertical shaft, said oil passage providing communication between said vertical shaft bearing surfaces, a thrust bearing on said Vertical shaft, an oil reservoir, a spiral oil groove, said spiral oil groove providing communication between said oil reservoir and said oil passage in sad vertical shaft, and a spiral oil groove, said last mentioned spiral oil groove providing communication between said oil passage in said Vertical shaft and said thrust bearing.

11. In a machine of the class described, in combination, an outer housing having a lubricant reservoir formed in the lower portion thereof, an inner housing enclosed by said outer housing, said inner housing being formed to provide a cylinder and crank case, said crank case being positoned above the maximum level of lubricant maintainable in said reservoir, pumping mechanism including a crank in said case and a piston in said cylinder, means for supplying lubricant to the pumping mechanism within said crank case,,and means for continuously retuming lubricant from said crank case to said reservoir whereby to prevent any accumulation of oil in the crank case.

12. In a machine of the class described, in'

combination, an outer housing having a lubricant reservoir formed in the lower portion thereof, an inner housing enclosed by said outer housing, said inner housing being formed to provide a cylinder and crank case, said crank case being positioned above the maximum level of lubricant maintainable in said reservoir, pumping mechanism including a crank in said case and a piston in said cylinder, a fluid inlet passage extending through said outer housing to said crank case, a valve passage in the head of said piston, a fluid outlet passage extending from the head of said cylinder through the outer housing, means for supplying lubricant to the pumping mechanism within said crank case, and means for continuously returning lubricant from said crank case to said reservoir whereby to prevent any accumulation of oil in the crank case.

ALLEN 'I'RASK. 

